Reply to Brian and Walker-Hale: Support for the island rule does not hide morphological disparity in insular plants

Abstract Recently it was proposed that the entanglement entropy of the Hawking radiation contains the information of a region including the interior of the event horizon, which is called “island.” In studies of the entanglement entropy of the Hawking radiation, the total system in the black hole geometry is separated into the Hawking radiation and black hole. In this paper, we study the entanglement entropy of the black hole in the asymptotically flat Schwarzschild spacetime. Consistency with the island rule for the Hawking radiation implies that the information of the black hole is located in a different region than the island. We found an instability of the island in the calculation of the entanglement entropy of the region outside a surface near the horizon. This implies that the region contains all the information of the total system and the information of the black hole is localized on the surface. Thus the surface would be interpreted as the stretched horizon. This structure also resembles black holes in the AdS spacetime with an auxiliary flat spacetime, where the information of the black hole is localized at the interface between the AdS spacetime and the flat spacetime.

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Replica wormholes for an evaporating 2D black hole

Journal of High Energy Physics ◽

10.1007/jhep04(2021)289 ◽

2021 ◽

Vol 2021 (4) ◽

Author(s):

Kanato Goto ◽

Thomas Hartman ◽

Amirhossein Tajdini

Keyword(s):

Black Holes ◽

Black Hole ◽

Path Integral ◽

Island Rule ◽

Technical Challenge ◽

Local Boundary ◽

Lorentzian Signature ◽

Special Cases ◽

Non Local ◽

Non Local Equations

Abstract Quantum extremal islands reproduce the unitary Page curve of an evaporating black hole. This has been derived by including replica wormholes in the gravitational path integral, but for the transient, evaporating black holes most relevant to Hawking’s paradox, these wormholes have not been analyzed in any detail. In this paper we study replica wormholes for black holes formed by gravitational collapse in Jackiw-Teitelboim gravity, and confirm that they lead to the island rule for the entropy. The main technical challenge is that replica wormholes rely on a Euclidean path integral, while the quantum extremal islands of an evaporating black hole exist only in Lorentzian signature. Furthermore, the Euclidean equations for the Schwarzian mode are non-local, so it is unclear how to connect to the local, Lorentzian dynamics of an evaporating black hole. We address these issues with Schwinger-Keldysh techniques and show how the non-local equations reduce to the local ‘boundary particle’ description in special cases.

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Morphological disparity in the evolution of the ophthalmosaurid forefin: new clues from the Upper Jurassic of Argentina

Papers in Palaeontology ◽

10.1002/spp2.1374 ◽

2021 ◽

Author(s):

Lisandro Campos ◽

Marta S. Fernández ◽

Yanina Herrera ◽

Alberto Garrido

Keyword(s):

Upper Jurassic ◽

Morphological Disparity

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Island rule and bone metabolism in fossil murines from Timor

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz197 ◽

2020 ◽

Vol 129 (3) ◽

pp. 570-586 ◽

Cited By ~ 2

Author(s):

Justyna J Miszkiewicz ◽

Julien Louys ◽

Robin M D Beck ◽

Patrick Mahoney ◽

Ken Aplin ◽

...

Keyword(s):

Body Weight ◽

Bone Metabolism ◽

Late Quaternary ◽

Phylogenetic Signal ◽

Skeletal Growth ◽

Island Rule ◽

Slow Pace ◽

Osteocyte Lacunae ◽

Murine Rodents ◽

Negative Relationships

Abstract Skeletal growth rates reconstructed from bone histology in extinct insular hippopotamids, elephants, bovids and sauropods have been used to infer dwarfism as a response to island conditions. Limited published records of osteocyte lacunae densities (Ot.Dn), a proxy for living osteocyte proliferation, have suggested a slower rate of bone metabolism in giant mammals. Here, we test whether insularity might have affected bone metabolism in a series of small to giant murine rodents from Timor. Ten adult femora were selected from a fossil assemblage dated to the Late Quaternary (~5000–18 000 years old). Femur morphometric data were used in computing phylogenetically informed body mass regressions, although the phylogenetic signal was very low (Pagel’s λ = 0.03). Estimates of body weight calculated from these femora ranged from 75 to 1188 g. Osteocyte lacunae densities from histological sections of the midshaft femur were evaluated against bone size and estimated body weight. Statistically significant (P < 0.05) and strongly negative relationships between Ot.Dn, femur size and estimated weight were found. Larger specimens were characterized by lower Ot.Dn, indicating that giant murines from Timor might have had a relatively slow pace of bone metabolic activity, consistent with predictions made by the island rule.

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Palaeohistology reveals a slow pace of life for the dwarfed Sicilian elephant

Scientific Reports ◽

10.1038/s41598-021-02192-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Meike Köhler ◽

Victoria Herridge ◽

Carmen Nacarino-Meneses ◽

Josep Fortuny ◽

Blanca Moncunill-Solé ◽

...

Keyword(s):

Life History ◽

Body Mass ◽

Growth Period ◽

Extended Period ◽

Island Rule ◽

Rule Based ◽

Age At First Reproduction ◽

Slow Pace ◽

First Reproduction ◽

Adaptive Shifts

AbstractThe 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be ‘r-selected’ by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals.

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Impact of transition to a subterranean lifestyle on morphological disparity and integration in talpid moles (Mammalia, Talpidae)

BMC Evolutionary Biology ◽

10.1186/s12862-019-1506-0 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 5

Author(s):

Gabriele Sansalone ◽

Paolo Colangelo ◽

Anna Loy ◽

Pasquale Raia ◽

Stephen Wroe ◽

...

Keyword(s):

Evolutionary Biology ◽

Morphological Variability ◽

Phenotypic Integration ◽

Phenotypic Traits ◽

Phenotypic Evolution ◽

Morphological Disparity ◽

Morphological Diversification ◽

Phylogenetic Conservatism ◽

Selective Forces ◽

Subterranean Species

Abstract Background Understanding the mechanisms promoting or constraining morphological diversification within clades is a central topic in evolutionary biology. Ecological transitions are of particular interest because of their influence upon the selective forces and factors involved in phenotypic evolution. Here we focused on the humerus and mandibles of talpid moles to test whether the transition to the subterranean lifestyle impacted morphological disparity and phenotypic traits covariation between these two structures. Results Our results indicate non-subterranean species occupy a significantly larger portion of the talpid moles morphospace. However, there is no difference between subterranean and non-subterranean moles in terms of the strength and direction of phenotypic integration. Conclusions Our study shows that the transition to a subterranean lifestyle significantly reduced morphological variability in talpid moles. However, this reduced disparity was not accompanied by changes in the pattern of traits covariation between the humerus and the mandible, suggesting the presence of strong phylogenetic conservatism within this pattern.

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